Hi Julia!
Thank you for bringing your question to the Disney Parks Moms Panel!
I love that you plan to run the Disney Princess Half Marathon Weekend events as a family. Some of my favorite family vacations have been during race weekends. There are race distances for all of us, and so many great places to eat in celebration of our achievements!
I recently registered my family and friends for events during Walt Disney World Marathon Weekend. I was able to register them all through my
runDisney account. After registering myself, I chose the option to "register someone else" and then was able to choose whether they were a family member, friend, etc. However, I do not believe there are any "team registrations" available for these events.
Registration for Disney Princess Half Marathon Weekend opens at noon ET/ 9 a.m. PT on August 8, 2018. I recommend having your runDisney account created in advance so you can get into the registration queue quicker.
I hope this helps. Please let me know if you have any other questions as you prepare for your runDisney race!